Genomic Epidemiology of Staphylococcus aureus Among Native American Populations in Southwestern United States

Staphylococcus aureus causes millions of infections in the US annually, and each year, at least 72,000 cases of severe invasive disease and 10,000 deaths are attributed to the difficult-to-treat methicillin-resistant S. aureus (MRSA). Historically, Native Americans and indigenous people in general have been burdened by high rates of infectious disease, an there are data to suggest the rate of S. aureus invasive disease among Native Americans may be double that of the general population. However, few studies of S. aureus have been conducted among these populations and surveillance data, which are integral for control efforts, remain limited. Consequently, little is known about the burden of invasive disease, asymptomatic carriage rates, antibiotic resistance prevalence, and transmission dynamics in these communities. Identifying disparities in these rates and elucidating routes of transmission have direct implications for control efforts among indigenous people and epidemiologically similar communities abroad. In this study, we seek to determine the comparative importance of host and pathogen factors associated with rates of disease among Native Americans. To this end, we are investigating the genomic epidemiology of S. aureus among Native Americans living on or around Navajo Nation or White Mountain Apache (N/WMA) tribal lands, identifying invasive disease among individuals seeking care at healthcare facilities, assessing carriage in the community, and investigating host and pathogen factors associated with carriage, disease, and transmission. Understanding the genomic epidemiology of S. aureus provides tools to control it. Reduction of disease rates depends on preventing transmission, and our determination of risk factors will identify high-risk populations that can be targeted for preventive interventions. Further, we will address larger evolutionary questions regarding the emergence and spread of S. aureus lineages and the adaptive evolution of clinically relevant traits. Our long-term goal is to understand the underlying factors precipitating a disproportionate burden of disease and the interaction between SA and other respiratory bacteria.

Funding: K22AI141582-01 NIH/NIAID